Opening the Settings menu and Selecting the My Account tab there is an button that will allow you to make an email change request.
Selecting the Change Email button will bring you to the request submission screen where you can enter and verify your new email and submit the change.
Alternatively, you can select the Manage Subscription button in the app to be taken to the online customer portal. There you can select Edit Profile to change your email and password to your account.
Once done with your changes you can select the Save Profile button to save your changes.